Indications for imaging

It is possible to predict reliably, on clinical criteria alone, patients at moderate or high risk of having intracranial hemorrhage. Cranial CT is preferred as the first and only examination for this purpose, and skull radiography should be dispensed with ( M°s,eley 1995). CT is likely to show depressed or compound fractures and the presence of foreign bodies better than skull radiographs, and may adequately define facial and other injuries as well. CT should be available within 4 h for the following indications (Royal CojJ®g®.9LR§dio.iogi.sts.„Working P.ady.J.995): impaired or fluctuating consciousness, the unassessable (intoxication, young children), patients at special risk (e.g. those with previous craniotomy, clinical deterioration, or failure to improve), neurological signs, or seizures. Most orbital and facial injuries do not require urgent investigation.

Plain radiography of the cervical spine is indicated only in the unconscious or unassessable patient, or when there is clinical evidence of neck injury; however, up to 30 per cent of injuries occur at C7-T1 level, which may not be well visualized. In patients with severe head injuries, fractures of C1, C2, or the occipital condyles may be shown by cranial CT; only about a third of these are recognizable on plain radiographs, suggesting that the initial cranial CT should include the spine down to the body of C3.

The digitally acquired scout scan (or scanogram) used to plan CT can be very useful in demonstrating regions such as the cervicothoracic junction and will exclude most major injuries detectable by plain radiography.

Serial CT in the absence of clinical deterioration is not required; however, an examination at discharge or transfer is desirable. The main abnormality detected on planned delayed CT is hydrocephalus, usually from 2 to 12 weeks after injury.

MRI is not generally recommended in the early management of patients; however, it may be helpful as a planned delayed investigation to assess prognosis ( Gentry

Some form of angiography may be needed in rare situations, such as diagnosing and guiding treatment of complications such as severe bleeding, false aneurysms, or arteriovenous fistulas.